1. Field of the Invention
This invention relates to a socket contact.
2. Description of the Related Art
Conventionally, as shown in FIGS. 11 and 12, there has been proposed a charging connector terminal 955 (socket contact) including an electric contact portion 913 having a hollow cylindrical shape, and an auxiliary spring (spring member) 963 which has an annular shape and is fitted on an outer periphery of the electric contact portion 913 (see Japanese Patent Laid-Open Publication No. H8-222314).
Four slits 957 extending in the direction of the central axis of the electric contact portion 913 are formed in the hollow cylindrical electric contact portion 913, at equally-spaced intervals in a circumferential direction of the electric contact portion 913, whereby the electric contact portion 913 is divided into four contact plates 959. Front end portions of the four contact plates 959 are elastically deformable in respective radial directions of the electric contact portion 913. Outer grooves 961 extending in the circumferential direction of the electric contact portion 913 are formed in respective outer peripheries of the four contact plates 959.
The inner diameter of the auxiliary spring 963 is slightly smaller than the outer diameter of the electric contact portion 913. The auxiliary spring 963 is fitted in the outer grooves 961.
When an electric contact portion 921A, which has a pin shape, of a male terminal 921 is inserted into the electric contact portion 913 of the charging connector terminal 955, the respective front end portions of the four contact plates 959 are displaced outward, whereby the diameter of the auxiliary spring 963 is increased. At this time, the inner peripheries of the front end portions of the contact plates 959 are pressed against the outer periphery of the electric contact portion 921A of the male terminal 921, by the returning forces of the contact plates 959 and the auxiliary spring 963, whereby predetermined contact forces are generated between the front end portions of the contact plates 959 of the charging connector terminal 955 and the electric contact portion 921A of the male terminal 921.
As described above, for the charging connector terminal 955, a structure is employed in which the auxiliary spring 963 is fitted in the outer grooves 961 formed in the outer peripheries of the four contact plates 959, and hence holding forces with which the outer grooves 961 hold the auxiliary spring 963 are small, so that there is a fear that the auxiliary spring 963 is easily removed from the electric contact portion 913.
Further, in the case of the structure including the outer grooves 961 formed in the outer peripheries of the four contact plates 959, the socket contact is manufactured by cutting, and hence the amount of waste material is large. This is one of factors which increase the manufacturing costs of the socket contact (charging connector terminal 955).